I have just started looking at v3.0 having developed a couple of sites using 2.4. I have come across one problem which I am sure is something I am doing wrong, but I can not see what the problem might me.
I have installed a basic site and created a new theme. In the admin panel I select the new theme and it was detected and displayed correctly.
I then created a new page (TestPage.php), put the template (TestPage.ss) in to the correct directory. Both were simple and TestPage.ss was just a copy of Page.ss. I viewed the pages and the new page was not rendered using the new theme but was continued to use the simple theme, unlike the other pages. It did not seem to be picking up the TestPage.ss file at all. (I rebuilt the site, and flushes caches just incase)
I then changed the theme in the _config.php file for the site to the new one and all the pages were displayed correctly and the TestPage.ss file was picked up correctly.
Is there any reason why setting through through the admin panel might not work?
I hope that the above makes sense and that some one can shed some light on this problem